I found the ebay auction for you, 66/67 Nova bucket seat tracks, media blasted. This is the ebay# 170453606959 the current bid is $41 and there is 4 days and 19 hours left.
Chevy 11 Only in Mount Washington Kentucky has them at $84.95 per side, #69171 left and #69172 right. Their phone # is 502-239-8487, I have bought parts from them, ask them to ship using the U.S Postal system to avoid broker fees.
I just can't let this post go without stating the obvious. When you post a request for information or parts how about telling us the year, make and model of the car. It isn't that we couldn't have taken a guess but why do we need to. You might have gotten more than one response and could have even found a used set for half the price but the fact is some guys won't even bother asking if you don't bother posting the information.